Intraoral scanning device with defogging element and protective sleeve

ABSTRACT

An intraoral scanning device comprises housing comprising a head configured for insertion into a patient oral cavity, the head comprising a sloped surface and an aperture for transmission of optical signals, a transparent element positioned within the aperture, wherein the transparent element is at an acute angle with respect to the sloped surface, and a defogging unit comprising a heating unit. The intraoral scanning device further comprises a protective sleeve configured to cover at least a part of the head when the protective sleeve is coupled to the housing. The protective sleeve comprises an additional aperture that aligns with the aperture and an additional transparent element in the additional aperture. A gap separates the additional transparent element from the transparent element when the protective sleeve is coupled to the housing, and heat generated by the heating unit is transferred from the heating unit to the additional transparent element despite the gap that separates the additional transparent element from the transparent element.

RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 16/105,916, filed Aug. 20, 2018, which is a divisional of U.S.patent application Ser. No. 14/192,137, filed Feb. 27, 2014, both ofwhich are incorporated by reference herein.

BACKGROUND

Temperature differences between a patient's body, e.g., oral cavity,stomach cavity, etc., and the surrounding ambient environment may causecondensation to form on a window of a medical device. A medical devicemay be for example, a scanning device, scope, optical instrument, etc.Condensation may interfere with the optical operation of the medicaldevice. For example, condensation may cause a change in the opticalsignal (by causing the light to diffract, refract, etc.) that maydegrade the optical signal resulting in images with degraded imagequality, such as blurry images.

Accordingly, various systems have been developed to defog windows ofdevices. For example, a fan or an air-pump may be used to blow air todefog the window. The air blown by the fan may or may not be heated.However, for the example where the device is a medical device, using afan to blow air may cause discomfort due to patient sensitivity, e.g.tooth sensitivity. Further, the addition of a fan increases energyusage, occupies valuable space, and generates noise. In another examplesystem, an opaque foil heater may be used to defog the window of thedevice. However, the opaque foil heater can degrade the transmission ofoptical signals. In another example system, the sides of the window ofthe device may be heated. However, heating the sides of the window maynot be sufficient to defog the window as a majority of the heat maydissipate through the ambient environment before reaching the morecentral portions of the window.

SUMMARY

Accordingly a need has arisen to defog transparent elements or windowsof optical devices without substantially degrading the transmission ofoptical signals and in the case of medical devices, with minimaldiscomfort to patients. Moreover, a need has arisen to defog windows inthe optical footprint (or optical profile) of an optical device whileminimally impacting the size and the amount of power the optical deviceconsumes. Furthermore, a need has arisen to defog windows of the opticaldevices without noise generation.

According to one embodiment, a thermal defogging system may be used toreduce condensation from forming on the transparent elements or windowsin an optical device. In one embodiment, the thermal defogging systemfor an optical instrument is comprised of: at least a primary housing,the primary housing defining an aperture for transmission of opticalsignals, a transparent element adapted to be aligned with the aperturefor transmission of optical signals, at least one side of thetransparent element facing the external environment; and a transparentconductive layer covering at least a portion of the transparent element,wherein responsive to the application of electrical power to thetransparent conductive layer, the transparent conductive layer generatesheat that is thermally communicated to the least one side of thetransparent element facing the external environment.

It will become apparent to those skilled in the art after reading thedetailed description that the embodiments described herein satisfy theabove mentioned needs in addition to other advantages.

BRIEF DESCRIPTION OF DRAWINGS

Embodiments are illustrated by way of example, and not by way oflimitation, in the figures of the accompanying drawings and in whichlike reference numerals refer to similar elements.

FIG. 1A shows a thermal defogging element in accordance with oneembodiment.

FIG. 1B shows an exemplary electrical connection in accordance with oneembodiment.

FIG. 1C shows a thermal defogging element with an electrical connectionin accordance with one alternative embodiment.

FIG. 1D shows a thermal defogging element with an electrical connectionin accordance with one alternative embodiment.

FIG. 1E shows a magnetically activated thermal defogging element inaccordance with one embodiment.

FIGS. 1F-1I show exemplary thermal defogging elements according tovarious embodiments.

FIGS. 2A-2D show components of a thermal defogging system according toone embodiment.

FIGS. 3A-3C show a device with a thermal defogging system according toan alternative embodiment.

FIGS. 4A-4D show a device with a thermal defogging system according toan alternative embodiment.

FIGS. 5A-5C show positioning of temperature sensors associated with thethermal defogging element according to various embodiments.

FIG. 6 shows a thermal defogging system according to one embodiment.

FIG. 7 shows an exemplary flow diagram of operation of a thermaldefogging system according to one embodiment.

DETAILED DESCRIPTION

References are made in detail to embodiments, examples of which areillustrated in the accompanying drawings. While the embodiments aredescribed in conjunction with the drawings, it is understood that theyare not intended to limit the embodiments. The embodiments are intendedto cover alternatives, modifications and equivalents. Furthermore, inthe detailed description, numerous specific details are set forth inorder to provide a thorough understanding. However, it is recognized byone of ordinary skill in the art that the embodiments may be practicedwithout these specific details. In other instances, known methods,procedures, components, and circuits have not been described in detailas to not obscure aspects of the embodiments. The foregoing description,for purpose of explanation, has been described with reference tospecific embodiments. However, the illustrative discussions are notintended to be exhaustive or to limit the invention to the precise formsdisclosed. Many modifications and variations are possible in view of theteachings. The implementations described and other implementations arewithin the scope of the following claims.

Some portions of the detailed descriptions that follow are presented interms of procedures, logic blocks, processing, and other symbolicrepresentations of operations on data bits within a computer memory.These descriptions and representations are the means used by thoseskilled in the data processing arts to most effectively convey thesubstance of their work to others skilled in the art. In the presentapplication, a procedure, logic block, process, or the like, isconceived to be a self-consistent sequence of operations or steps orinstructions leading to a desired result. The operations or steps arethose utilizing physical manipulations of physical quantities. Usually,although not necessarily, these quantities take the form of electricalor magnetic signals capable of being stored, transferred, combined,compared, and otherwise manipulated in a computer system or computingdevice. It has proven convenient at times, principally for reasons ofcommon usage, to refer to these signals as transactions, bits, values,elements, symbols, characters, samples, pixels, or the like. It shouldbe borne in mind that all of these and similar terms are to beassociated with the appropriate physical quantities and are merelyconvenient labels applied to these quantities. Unless specificallystated otherwise as apparent from the following discussions, it isappreciated that throughout the present disclosure, discussionsutilizing terms such as “supplying,” “measuring,” “comparing,”“generating,” “storing,” “adjusting,” “transmitting,” “receiving,”“providing,” “accessing,” or the like, refer to actions and processes ofa computer system or similar electronic computing device or processor.The computer system or similar electronic computing device manipulatesand transforms data represented as physical (electronic) quantitieswithin the computer system memories, registers or other such informationstorage, transmission or display devices.

A thermal defogging system and method for an optical instrument isdescribed. In one embodiment, the thermal defogging system for anoptical instrument is comprised of: at least a primary housing, theprimary housing defining an aperture for transmission of opticalsignals, a transparent element adapted to be aligned with the aperturefor transmission of optical signals, at least one side of thetransparent element facing the external environment; and a transparentconductive layer covering an area at least as large as the opticalfootprint of the transmitted optical signal through the transparentelement, wherein responsive to the application of electrical power tothe transparent conductive layer, the transparent conductive layergenerates heat that is thermally communicated to the least one side ofthe transparent element facing the external environment.

In one embodiment, the thermal defogging system includes a thermaldefogging element 100 comprised of a transparent element 110 (atransparent substrate) that is coated with a transparent conductivelayer 120. According to one embodiment, the thermal defogging element100 may be aligned to an aperture of a device, e.g., scanning device,scope, optical instrument, etc. The thermal defogging element heats upto a predetermined set temperature in response to receiving electricalpower, thereby removing condensation. The condensation may result fromhumidity from patient's internal cavity and a temperature differencebetween the ambient temperature and the temperature of patient'sinternal cavity. The patient's internal cavity may include oral cavity,stomach cavity, etc.

It is appreciated that the thermal defogging element may be integratedwithin a housing of the device. In one embodiment, the thermal defoggingelement is integrated into the device housing and is not removableduring ordinary use. In an alternative embodiment, the thermal defoggingelement may be removable, thereby allowing it to be disinfected afteruse. In another embodiment, the thermal defogging element may beremovable and disposable such that it can be replaced with a new thermaldefogging element after use with each patient.

The thermal defogging system includes at least a primary housing thathouses the optical instrument. In one example, the defogging system alsoincludes a secondary housing that physically surrounds the primaryhousing. It is appreciated that according to various embodiments, thethermal defogging element may be isolated from a patient's body, e.g.,oral cavity, by the secondary housing. In one example, the secondaryhousing prevents contact between the thermal defogging element and thepatient's body and allows the thermal defogging element to be reusedwithout a need to disinfect and/or replace the thermal defoggingelement.

It is appreciated that for illustration purposes, various embodimentsare described in relation to medical devices and defogging of thetransparent elements or transparent windows associated therewith.However, the specifics discussed are merely illustrative in nature andare not intended to be limited by the scope of the embodiments. Forexample, embodiments described herein are equally applicable to othertypes of devices where defogging of a window is required. It isappreciated that for illustration purposes, various embodiments aredescribed in relation to oral cavities and temperatures associatedtherewith. However, the specifics discussed are merely illustrative innature and are not intended to limit the scope of the embodiments. Forexample, embodiments described herein are equally applicable to othermedical devices used for other body cavities such as the stomach cavityduring surgery, etc.

Referring now to FIG. 1A shows a thermal defogging element 100 inaccordance with one embodiment. In the embodiment shown, the thermaldefogging element 100 is comprised of a transparent element 110 (orsubstrate) and a transparent conductive layer 120. The thermal defoggingelement has high optical transmission properties, e.g., greater than90%, greater than 97%, etc. In one example, the transparent conductivelayer covers an area at least as large as the optical footprint of thetransmitted optical signals through the transparent element. In oneembodiment, the transparent conductive layer 120 coats or is formed onthe surface of the transparent element 110. It is appreciated that thetransparent element and the transparent conductive layer 120 are bothtransparent. It is further appreciated that transparent layers,transparent conductive layers, transparent elements or substrates, asused throughout the detailed description, refer to material that havehigh optical transmission properties, e.g., at least 90%, at least 97%,etc. transmissibility properties. It is noted that terms thermaldefogging element and defogging element are used interchangeablythroughout this detailed description. According to one embodiment, thetransparent element 110 is a glass substrate. However in variousembodiments, other transparent substrates may be used. For example, thetransparent element 110 may be comprised of a transparent plastic or atransparent polycarbonate material. The thickness of the transparentelement 110 may vary depending on application. For example, in oneembodiment the thickness of the transparent substrate 110 may be between0.75 mm to 1 mm. As previously stated, in one embodiment the thermaldefogging element 100 includes a transparent element 110 that is coatedwith a transparent conductive layer 120. In one exemplary embodiment,the conductive layer 120 is a very thin submicron layer comprised of amaterial that when power is applied, generates heat, such as anelectrically resistive layer. In one example, the transparent conductivelayer is a thin layer of a metal compound such as indium tin oxide.According to some embodiments, a conductive layer 120 other than indiumtin oxide may also be used. For example, a fluorine tin oxide, analuminum tin oxide or gold layer may similarly be used. As such,references to indium tin oxide are merely exemplary and not intended tolimit the scope of the embodiments described herein. The transparentconductive layer 120 may be applied to the transparent substrate 110using different processes. In an alternative embodiment, the conductivematerial (for example, indium tin oxide) is scattered over thetransparent substrate 110. In one example, the transparent conductivelayer 120 is applied and the thickness precisely controlled by adeposition process.

According to one embodiment, the transparent conductive layer 120, whichis deposited over the transparent element 110 has an electricalresistance. This electrical resistance causes the transparent conductivelayer 120 to heat up once a specific voltage value is applied to it.This voltage is also known as an activation voltage. The resistance ofthe transparent conductive layer 120 may be measured in ohms per squareunit. As such, the length (for example as shown in FIG. 1C) of thetransparent element 110 that the conductive layer 120 is deposited overproportionally impacts the resistance of the conductive layer 120. Also,the resistance value is inversely impacted by the width (shown in FIG.1C) of the transparent element 110. According to one embodiment, auniform heat flux is generated by the thermal defogging element 100 ifthe length of the thermal defogging element 100 does not vary withrespect to the electrical connections (electrical bars 160 shown in FIG.1C). In other words, the geometry of the thermal defogging element 100determines whether a uniform or non-uniform heat flux is generated bythe thermal defogging element 100.

In one embodiment, the transparent conductive layer 120 may be furthercoated with a dielectric insulating layer (not shown), therebyprotecting the transparent conductive layer 120. In the embodiment wherea dielectric insulating layer is deposited over the transparentconductive layer, the dielectric layer can act as a protective coatingto prevent the transparent conductive layer from wearing off or beingdamaged during use. The protective function of the dielectric insulationlayer can be helpful because the transparent conductive layer can bevery thin (micro-millimeters) and can be easily damaged. In addition toa protective function, the dielectric insulating layer can provide aninsulating function, thus preventing the conductive layer from makingelectrical shorts with surrounding conductive objects. The dielectricinsulating layer may further be used for optical index matching theconductive layer 120 to the surrounding ambient environment, e.g., air,body cavity, etc. In addition, the dielectric insulation layer may be anon-glare layer that the transparent conductive layer 120 may be coatedwith to create an anti-reflective coating.

Referring now to FIG. 1B, an exemplary electrical connection inaccordance with one embodiment is shown. Modular contacts may be used tosupply power to the thermal defogging element. For example, the modularcontacts may include spring type connectors 140 positioned over aconnector base 130 to make electrical connection to the conductive layer120. It is appreciated that the spring type connectors 140 contract andexpand accordingly to grip the thermal defogging element and makeelectrical contact with the conductive layer 120. Accordingly, oncepower is supplied via the spring type connectors 140, the thermaldefogging element becomes operational and its conductive layer 120 heatsup, thereby removing condensation. It is appreciated that other types ofelectrical connections may be used, as discussed below.

Referring now to FIG. 1C, a thermal defogging element with an electricalconnection in accordance with one alternative embodiment is shown. Athermal defogging element 100 is substantially similar to the thermaldefogging element 100 discussed with respect to FIG. 1A. In thisembodiment, power may be provided to the thermal defogging element 100via a flex circuit 180. The flex circuit 180 may include electricalwires 150 for conducting electricity and power to the thermal defoggingelement 100. The electrical wires 150 provide power to electrical bars160 that are in contact with the transparent conductive layer 120 of thethermal defogging element 100. The electrical bars 160 may also bereferred to as bus bars. The electrical bars 160 may make electricalcontact with the transparent conductive layer 120 by being soldered,printed, deposited, glued, or scattered over the conductive coatinglayer 120. In an embodiment where a dielectric insulation layer isdeposited over the transparent conductive layer 120, the electrical bars160 may be disposed on the dielectric insulation layer and penetrate thedielectric layer to provide an electrical connection to the conductivelayer 120. In various embodiments, the electrical bars 160 may be gluedto the transparent conductive layer 120 using, for example, electricallyconductive glue. It is appreciated that an electrically conductiveadhesive or foam over the electrical bars 160 and wires embedded insidethe adhesive may also make the electrical connection between theelectrical bars 160 and the electrical power source. In the embodimentshown in FIG. 1C, two electrical bars 160 are shown parallel to oneanother. As such, uniformly coating the transparent substrate 110 withthe conductive coating layer 120 causes the heat flux to be generateduniformly throughout the surface. It is appreciated that using twoelectrical bars 160 is merely exemplary and not intended to limit thescope of the embodiments. For example, embodiments may include one ormore electrical bars, various other electrically conductive shapesand/or materials, non-parallel electrically conductive bars, etc.Furthermore, it is appreciated that the thermal defogging element 100may be shaped based on the shape of the aperture formed in the housingof the device. For example, the thermal defogging element 100 may berectangular, square, elliptical, circular, etc., based on the apertureof the device.

As previously stated, the thermal defogging element 100 shape may be onthe shape of the aperture of the device. In one example, the shape ofthe aperture may be smaller than the transparent element. In oneembodiment shown in FIG. 1D, the shape of the transparent conductivelayer 120 of the thermal defogging element 100 matches the shape of theaperture of the defogging element housing. The embodiment shown in FIG.1D is similar to the embodiment shown in FIG. 1C. However, in FIG. 1D,instead of extending over substantially the entire substrate (to theedge or substantially to the edge of the transparent element as shown inFIG. 1C), the transparent conductive layer 120 extends only across alimited portion of the transparent element—an area that mirrors the sizeof the aperture.

For purposes of discussion, assume that the transparent element 110shown in FIG. 1C is identical to the transparent element 110 shown inFIG. 1D. The area of the transparent conductive layer shown in FIG. 1Cis equal to L₁ multiplied by W₁. However, although the length and widthof the substrate over which the conductive layer is deposited are thesame, the transparent conductive layer shown in FIG. 1D is smaller inarea than the electrically conductive layer shown in FIG. 1D. In theexample shown in FIG. 1D, the area of the transparent conductive layer120 is equal to length L₂ multiplied by a width W₂, where L₂<L₁ andwhere W₂<W₁. Referring now to FIG. 1E, a magnetically activated thermaldefogging element in accordance with one embodiment is shown. Power maybe provided, by various means, to the thermal defogging element 100 inorder to heat up the thermal defogging element 100. For example, insteadof providing an electrical connection, as shown in FIGS. 1B-1D, amagnetic field 190 may provide the necessary energy. As such, themagnetic field 190 may cause the transparent conductive layer 120 of thethermal defogging element to heat up. In this example, magnetic field190 may be provided using a wire carrying current that is positioned inclose proximity to the thermal defogging element. It is appreciated thatthe magnetic field may be provided using other means, e.g., using astator assembly, coil, etc. According to one embodiment, a magneticfield may be used to induce an Eddy current on the conductive coatinglayer 120 of the thermal defogging element 100 causing it to heat up. Inembodiments where power is provided using a magnetic field 190,electrical connections as discussed with respect to FIGS. 1B, 1C and 1Dmay be eliminated. Therefore, it is appreciated that power may beprovided to the thermal defogging element using other means. Furtherexamples may include the conductive coating layer 120 having chemicalcompounds that heat up in response to receiving light with certainwavelength, e.g., ultraviolet, etc. As such, the thermal defoggingelement may heats up in the presence of light of a certain wavelength oflight.

Referring now to FIGS. 1F-1I, exemplary thermal defogging elementsaccording to various embodiments are shown. FIG. 1F shows a thermaldefogging element with a flex circuit 180 having electrical wires 150,electrical bars 160, and a defogging element 100 that are similar tothose as described in FIG. 1C. In the embodiment shown in FIG. 1F,however, a first region of the defogging element 100 and the electricalbars 160 are inclined at an angle somewhere between 0 degrees and 180degrees with respect to at second region of the defogging element. Forexample, the first region of the defogging element 100 and theelectrical bars 160 may be angled at midpoint, a quarter point, threequarter point, etc. with respect to a second region of the thermaldefogging element. In this non-limiting embodiment, the two electricalbars 160 are shown parallel to one another. As such, uniform heat fluxmay be generated by uniformly coating the transparent element 110 withthe transparent conductive layer 120 along with the two electrical bars160 that are equidistant from one another.

Referring now to FIGS. 1G-1I, exemplary thermal defogging elementsaccording to various embodiments are shown. In these embodiments, theflex circuits 180, the electrical wires 150, the electrical bars 160,and the defogging elements 100 operate substantially similar to thosedescribed above. However, in the embodiments shown in FIGS. 1G-1I, theelectrical bars 160 and the thermal defogging elements 100 are shapeddifferently based on the window aperture of the device. Any shape may beused including, for example, square, round, triangle, diamond,trapezoid, hexagon, rectangle, oval, etc. According to some embodiments,a non-uniform heat flux generation may be desired. Non-uniform heat fluxmay be generated using non-equidistant electrical bars, as shown in FIG.1G1I.

In some embodiments, uniform heat flux may be generated despite anon-uniform structure of the thermal defogging element. For example, thetransparent conductive layer 120 of the thermal defogging element may bedeposited non-uniformly based on shape and location of the electricalbars in order to generate heat uniformly. The resistance of thetransparent conductive layer 120 is based on the length of theconductive material between the electrical bars, i.e. a higher pathlength has a higher resistance. For example referring to FIG. 1I, thepath labeled “Lower Resistance” has a lower resistance value than thepath labeled “Higher Resistance” as the path labeled “Lower Resistance”is shorter in length. Thus in one example, a thinner conductive materiallayer may be deposited over a region of the thermal defogging elementwhere the electrical bars are closer together in comparison to otherregions to generate a uniform heat flux. As such, the resistance of theregion where the electrical bars are closer together is increased tosubstantially match the resistance of other regions in order to generatea uniform heat flux.

FIGS. 2A-2D shows parts of a thermal defogging system for an opticalinstrument or device according to one embodiment. Referring to FIG. 2Ashows a thermal defogging element (comprised of a transparent element110 and a transparent conductive layer 120) and its correspondingelectrical connections according to one embodiment. The thermaldefogging element is similar to the thermal defogging element andelectrical connections shown in FIGS. 1A, 1C-1D and 1F-1I. For example,comparing FIG. 2A to FIG. 1C, the electrical wires 150, electrical bars160 and flex circuit 180 shown in FIG. 1C provides similar functionalityand support as the electrical bars 160 and conductive connection bar 210a-b shown in FIG. 2A. In one example, a first region of the conductiveconnection bar 210 a electrically connects the electrical bars 160 tosecond region of the conductive connection bar 210 b. The second regionof the conductive connection bar 210 b connects the first region of theconductive connection bar 210 a to a power source (not shown).

Referring to FIG. 2B shows an optical element (a prism) 220 of theoptical device in position next to the thermal defogging element 100before insertion of the optical element 220 and thermal defoggingelement 100 into the primary housing. The embodiment shown in FIG. 2Cshows a view of the thermal defogging system after insertion of thethermal defogging element 100 and the optical element 220 inside of theprimary housing. As previously stated, in one example the thermaldefogging system includes at least a primary housing 250. In theembodiment shown in FIG. 2C, the primary housing 250 is also the housingof the optical device (the optical device housing). In the embodimentshown in FIG. 2C, the primary housing is a support structure responsiblefor maintaining the position of the thermal defogging element 100 sothat it is aligned with the optical footprint of the transmitted opticalsignals from the optical element. In addition, the primary housingdefines an aperture for transmission of optical signals from the opticalprism 220 (inside of the optical device) to an area external to theprimary housing (i.e. the patient cavity).

In the embodiment shown in FIG. 2C, the primary housing 250 supports thedefogging element 100 and positions it so the defogging element 100 isaligned with the aperture of the primary housing. At least one side ofthe transparent element of the defogging element 100 (transparentelement 110 coated with a transparent conductive layer 120) faces theexternal environment, the external surface 234 in FIG. 2D of thedefogging element. Responsive to the application of electrical power tothe transparent conductive layer, the transparent conductive layer ofthe defogging element 100 generates heat that is thermally communicatedto the at least one side of the defogging element facing the externalenvironment. In one embodiment, the transparent conductive layer of thedefogging element 100 is at least as large as the optical footprintgenerated by the optical instrument. In one example, the portion of thetransparent element that the transparent conductive layer extends overmatches the shape of the aperture formed by the primary housing.

In one embodiment, the external surface 234 of the defogging element 100is coated with a transparent conductive layer 120 and when power isapplied to the transparent conductive layer, the heat generated issufficient to prevent condensation from forming on the external surfaceof thermal defogging element so that the defogging element 100 (thewindow of the optical device) maintains its high optical transmissionproperties. In an alternative embodiment, the internal surface 232 ofthe defogging element 100 is coated with the transparent conductivelayer 120 and responsive to the application of power, the internalsurface 232 of the defogging element 100 is heated. In this example, theheat generated on the internal surface of the defogging element isthermally communicated from the internal surface 232 of the defoggingelement through the transparent element to the external surface 234 ofthe defogging element that faces the external environment. In oneembodiment, heat is thermally transmitted or communicated for example,by convection or conduction. For the example of a medical opticalinstrument, the heat transmitted to the external surface of thedefogging element should be sufficient to prevent condensation fromforming on the external surface of the defogging element when positionedinside a patient's cavity. In one example, the transparent element 110of the defogging element is glass. Although glass is not a particularlyefficient heat transmitter, the glass may be made sufficiently thin totransmit the heat required to prevent condensation from forming on theexternal surface of the defogging element.

In the embodiment shown in FIG. 2C, it is appreciated that in thisembodiment, the shape of the head of the optical device that is insertedinto the patient cavity, the optical device wand head, is trapezoidal inshape. However, it is appreciated that the trapezoidal shape of the wandhead is exemplary and should not be construed to limit the scope of theembodiment. For example, the wand head may be rectangular in shape. Itis further appreciated that although the defogging element is shownpositioned within an optical device head that is located at the end ofthe wand, in other embodiments the defogging element may be positionedat an alternative location within the optical device, displaced somepredetermined distance from the end of the wand.

FIG. 2D shows a cross-sectional view of the optical device and defoggingsystem shown in FIG. 2C. In one embodiment, the thermal defogging systemfor an optical device is comprised of: at least a primary housing, theprimary housing defining an aperture for transmission of opticalsignals, a transparent element adapted to be aligned with the aperturefor transmission of optical signals, at least one side of thetransparent element facing the external environment; and a transparentconductive layer covering an area at least as large as the opticalfootprint of the transmitted optical signal through the transparentelement, wherein responsive to the application of electrical power tothe transparent conductive layer, the transparent conductive layergenerates heat that is thermally communicated to the least one side ofthe transparent element facing the external environment.

Referring to FIGS. 2C and 2D, the thermal defogging system is comprisedof at least a primary housing 250, where the primary housing 250 definesan aperture for transmission of optical signals. Referring to theembodiment shown in FIGS. 2C and 2D, the aperture is the portion of thehousing that surrounds the defogging element. The aperture creates anopening that the optical signals from the optical element 220 cantransmit optical signals through. The transparent element 110 of thedefogging element 100 is adapted to be aligned with the aperture of theprimary housing for transmission of optical signals. At least one side234 of the transparent element faces the external environment 295. Inone example, the transparent conductive layer of the defogging element100 covers an area at least as large as the optical footprint of thetransmitted optical signal through the transparent element. Whenelectrical power is applied to the transparent conductive layer, thetransparent conductive layer of the defogging element 100 generates heatthat is thermally communicated to the at least one side of thetransparent element facing the external environment.

The transparent conductive layer covers at least a portion of thetransparent element. In one example, the transparent conductive layercovers all or substantially all of the surface of the transparentelement. As previously stated, in one example the transparent conductivelayer of the defogging element 100 covers an area at least as large asthe optical footprint of the transmitted optical signal through thetransparent element. In an alternative example (for example where theaperture defined by the primary housing is smaller than the opticalfootprint), then the transparent conductive layer may be the size of theaperture of the primary housing. In one example, the conductive film hasan annular share over the entire optical footprint or a portion of theoptical footprint of the transmitted optical signal. In alternativeexamples, the area that the transparent conductive film covers may be anarea that is only be a portion of the optical footprint. However, thearea of the transparent conductive film should be sufficient to generateenough heat to defog the at least one side of the transparent elementfacing the external environment along the optical footprint of thetransmitted signal.

In one embodiment, the primary housing 250 supporting and aligning thethermal defogging element to the aperture of the primary housing isdesigned to be permanently mechanically coupled to the thermal defoggingelement and thus the thermal defogging element is not easily removable.For example, for the optical device shown in FIG. 2D—the thermaldefogging element 100 can be removed from inside of the primary housinghowever, not without physically separating of the thermal defoggingelement from the primary housing and not without making the opticaldevice non-functioning. In an alternative implementation (not shown),electrical connection of the thermal defogging element 100 can be madeto optical device via electrical connectors that are externallyaccessible. For example, spring connectors similar to those shown inFIG. 1B could be positioned on the internal surface of the trapezoidalwand head such that the defogging element could be inserted into thespring contacts for providing an electrical connection from outside ofthe primary housing. This would allow the thermal defogging element tobe easily removable for replacement or alternatively easily available tobe disinfected after patient use. However, even with the removability ofthe thermal defogging element, the primary housing would still need tobe disinfected after each use in the event of patient contact.

When a medical device having the configuration shown in FIG. 2C entersfor example, the oral cavity of a patient, it is likely that the devicemay come into contact with the patient. Thus the embodiment shown inFIG. 2C will need to be disinfected after each use. Instead ofdisinfecting the optical instrument after each use, it may be desirableto provide a barrier between the optical instrument and the patientcavity into which the optical instrument may be inserted. In theembodiment shown in FIGS. 3A-3C and FIGS. 4A-4C, a physical barrier isplaced between the patient and the optical instrument, so that theoptical instrument and/or the defogging element of the opticalinstrument may not need to be disinfected after each use.

Referring now to FIGS. 3A-3C, shows parts of a thermal defogging systemaccording to one embodiment. The embodiment shown in FIGS. 3A-3C issimilar to the embodiment shown in FIGS. 2A-2D, except that theembodiment shown in FIGS. 3A-3C in addition a primary housing—thethermal defogging system also includes a secondary housing. Comparingthe implementation shown in FIGS. 2A-2D to FIGS. 3A-3C—in additionalchange is that instead of the thermal defogging element 100 beingsupported by the primary housing, the thermal defogging element 100 issupported by and integrated into the secondary housing. In oneembodiment the secondary housing may be removable.

In the embodiment shown in FIGS. 3A-3C, the secondary housing is anexternal sleeve that protects the optical instrument from contact with,for example, the patient's oral cavity. In the embodiment shown in FIGS.3A-3C, the defogging element 100 (the transparent element and thetransparent electrically conductive layer) is supported by andpositioned within the secondary housing. Referring to FIG. 3A shows asecondary housing 310 that acts as an external sleeve to protect theoptical instrument or medical device from contact with the patientcavity. FIG. 3B shows the primary housing 250 of the optical instrumentin accordance with one embodiment. FIG. 3C shows coupling of thesecondary housing 310 with the primary housing 250 in accordance withone embodiment. Referring to FIG. 3A, the thermal defogging systemincludes a secondary housing 310 that prevents fluids and othercontaminants from reaching the primary housing 250 of the device (shownin FIGS. 3B and 3C). According to one embodiment, the secondary housing310 may be removable. For example, the secondary housing 310 may beremoved and disinfected after use with each patient. Alternatively, thesecondary housing 310 may be disposable and replaced after use with eachpatient. In one example, the secondary housing may be made of plastic oranother inexpensive material. Further, in one embodiment, the defoggingelement 100 may be removable from the secondary housing 310. As such,the defogging element 100 may be removed and disinfected betweenpatients. Alternatively, the defogging element 100 may be disposable andreplaced after use with each patient.

Referring now to FIG. 3A, the defogging system includes a secondaryhousing 310 that supports a defogging element 100. The defogging element100 is similar to the thermal defogging elements previously discussed.In the embodiment shown in FIGS. 2A-2D, it is the primary housing 250that supports the defogging element. In the embodiment shown in FIGS.2A-2D both the external surface of the primary housing and the externalsurface 234 of the defogging element face the external environment. Inthe embodiment shown in FIGS. 3A-3C, it is the secondary housing 310(that supports the defogging element 100) and the external side 234 ofthe defogging element are in contact with the external environment295—while the primary housing that is enclosed within the secondaryhousing is not directly in contact with the external environment. Thesecondary housing 310 includes supports 320 that hold the defoggingelement 100 in place so that the transparent element of the defoggingelement is aligned with the window aperture of the primary housing.

In the embodiment shown in FIG. 3A, an aperture 340 is formed in thesecondary housing. When as shown in FIG. 3C, the primary and secondaryhousing are coupled together, optical signals travel from the opticalprism 220 to the aperture of the primary housing (element 252 shown inFIG. 3B) through the defogging element 100 through the aperture 340 ofthe secondary housing to the external environment 295 (i.e. thepatient's body cavity, e.g., oral cavity, stomach cavity, etc.

It is appreciated that the defogging element 100 that is housed withinthe secondary housing 310 is positioned to align with the aperture 352of the primary housing. The defogging element 100, by virtue of itstransparency, allows unaltered optical signals to travel between thepatient's body cavity and the medical device. The surface of thedefogging element 100 facing the aperture of the primary housing (afterthe primary housing is positioned inside the secondary housing) isreferred to as the internal surface of the defogging element 232. Thesurface of the defogging element 100 facing the external environment 295is referred to as the external surface of defogging element 234. In theembodiment shown in FIGS. 3A-3C, the defogging element is comprised of atransparent element that is coated with a transparent conductive layer.At least one side of the transparent element faces the externalenvironment 295. In one embodiment, the transparent conductive layercoating is on the external surface of the defogging element 234. In analternative embodiment, the transparent conductive layer is on theinternal surface of the defogging element 232. In either embodiment, thetransparent conductive layer generates heat that is thermallycommunicated to the side of the transparent element facing the externalenvironment.

While the defogging element 100 shown in FIG. 3A is shown in ahorizontal position or configuration, various embodiments may not belimited to such configurations. For example, the defogging element 100may be positioned such that it is at an angle with respect to thehorizontal plane. Positioning the defogging element 100 in a horizontalconfiguration or at an angle may provide the defogging element 100certain properties. For example, changing the angle of the defoggingelement 100 with respect to the horizontal plane may affect refractingproperties, reflecting properties, light index matching properties, etc.

Referring now to FIG. 3A shows a secondary housing 310 that supports adefogging element 100. A thermal defogging system and method for anoptical instrument is described. The thermal defogging system iscomprised of: a defogging element housing, the defogging element housingcomprising at least a primary housing, the primary housing defining anaperture for transmission of optical signals, a transparent elementadapted to be aligned with the aperture for transmission of opticalsignals, at least one side of the transparent element facing theexternal environment; and a transparent conductive layer covering atleast a portion of the transparent element, wherein responsive to theapplication of electrical power to the transparent conductive layer, thetransparent conductive layer generates heat that is thermallycommunicated to the least one side of the transparent element facing theexternal environment.

Referring now to FIG. 3B, the primary housing 250 of the optical deviceis shown. It is appreciated that the primary housing 250 supports andsurrounds the optical components 220, such as a prism and othercomponents necessary to support the functionality of the optical device.The primary housing 250 includes an aperture 352 in the primary housing.Optical signals may be transmitted and received between the aperture 352of the primary housing 250 and the patient's body cavity.

Referring now to FIG. 3C shows coupling of the secondary housing 310with the primary housing 250 in accordance with one embodiment. In theembodiment shown in FIG. 3C, the primary housing 250 is positionedinside of the secondary housing 310 so that the secondary housing actsas a protective sleeve to protect the primary housing 250. The apertureof the primary housing 352 is positioned to align with the aperture 340of the secondary housing. The transparent defogging element is alsoaligned with the aperture 340 of the secondary housing, thus enablingoptical signals to be communicated from the optical instrument to theexternal environment. The defogging element 100 is held in place by thesupports 320 of the secondary housing. The internal surface of defoggingelement 232 faces the aperture of the primary housing 352. The externalsurface of defogging element 234 faces and contacts the externalenvironment 295.

In the embodiment shown in FIGS. 3A-3C, when the primary housing iscoupled to the secondary housing as shown in FIG. 3C, the electricalconnectors 260 shown on the bottom of the primary housing in FIG. 3Bmake electrical connection to the defogging element 100. In one example,the transparent conductive layer is applied to the internal surface 232of the transparent element. In one embodiment, no dielectric layercovers the transparent conductive layer on the internal surface 232 andelectrical contact is made directly from the electrical connectors 360to the surface of the transparent conductive layer 120. In one example,the defogging element is similar to the defogging element in FIG. 1C andelectrical connection is made from the electrical connectors 360 to thebus bars on the side of the defogging element. In another example, adielectric layer (not shown) covers the transparent conductive layer andelectrical contact is made from the connectors 360 to electrical barswhich are connected to the transparent conductive layer.

In an alternative embodiment, instead of the transparent conductivelayer being applied to the internal surface 232 of the transparentelement—it can be applied to the external surface 234 of the transparentelement. In this case, an electrical connection from the electricalconnectors 360 on the base of the primary housing to the electricallyconductive layer on the external surface of the transparent elementwould need to be made in order to provide power to the electricallyconductive layer. It is appreciated that instead of having electricalconnectors 360, other types of connectors may be used, such as thespring connectors described in FIG. 1B. Furthermore, power may besupplied to the defogging element 100 through other means, e.g.,magnetic field, optically, etc., as discussed above, thereby eliminatingthe need to have electrical connectors.

The thermal defogging element may include a transparent element coatedwith a transparent conductive layer configured to generate heat inresponse to the application of power. For example, supplying power tothe defogging element 100 via the electrical connectors 260 generates aheat flux due to the transparent conductive layer 120 (FIG. 1A) and itsassociated resistance. In one embodiment, the generated heat fluxdissipates uniformly through the transparent substrate 110 (FIG. 1A) ofthe defogging element 100. In one embodiment, the transparent conductivelayer is configured to reach a predetermined temperature in response toreceiving power. The predetermined temperature of the transparentconductive layer is operable to prevent condensation from forming on theexternal surface of the thermal defogging element. As such, condensationformed on the external surface of the defogging element 234 due to adifference in temperature of the ambient air and the body cavity issubstantially reduced and/or eliminated. In applications to patient'smouth, oral cavity is approximately 36.5° C. Thus, heating the defoggingelement 100 to 38° C. eliminates condensation and fog formed on theexternal surface of the defogging element 234.

It is appreciated that the temperature of the defogging element 100 inthe device may be controlled using a controller, discussed below.Moreover, the thermal defogging element of the device may be programmedto reach and maintain a predetermined temperature depending on itsapplication and the surrounding temperature. Furthermore in variousembodiments, the temperature may be controlled manually, therebyallowing an operator to adjust defogging performance according to, forexample, individual preference. Temperature control of the thermaldefogging element is described in more detail with respect to FIGS. 6and 7 below.

In one embodiment, the defogging system can be described by theimplementation shown in FIG. 3A. For this case, the defogging system isthe secondary housing that acts as an external sleeve that fits over theprimary housing of the optical instrument. In the implementation shownin FIG. 3A, the defogging element is supported by the secondary housing.Referring to the defogging system shown in FIG. 3A is comprised of: asecondary housing, the secondary housing defining an aperture fortransmission of optical signals, a defogging element comprised of atransparent element and a transparent conductive layer, wherein thedefogging element is adapted to be aligned with the aperture of thesecondary housing and an aperture of a primary housing, wherein thetransparent conductive layer of the defogging element covers an area atleast as large as the optical footprint of the transmitted opticalsignal through the transparent element, wherein at least one side of thedefogging element faces the external environment, wherein responsive tothe application of electrical power to the transparent conductive layer,the transparent conductive layer generates heat that is thermallycommunicated to the least one side of the defogging element facing theexternal environment.

In an alternative embodiment, the defogging system can be described bythe implementation shown in FIGS. 2C and 2D in that it is comprised of:at least a primary housing, the primary housing defining an aperture fortransmission of optical signals, a transparent element adapted to bealigned with the window aperture for transmission of optical signals, atleast one side of the transparent element facing the externalenvironment; and a transparent conductive layer covering an area atleast as large as the optical footprint of the transmitted opticalsignal through the transparent element, wherein responsive to theapplication of electrical power to the transparent conductive layer, thetransparent conductive layer generates heat that is thermallycommunicated to the least one side of the transparent element facing theexternal environment. Referring now to FIGS. 4A-4D, shows parts of athermal defogging system according to an alternative embodiment. FIGS.4A and 4B illustrate different exemplary perspectives of the primaryhousing 4. FIG. 4C shows the secondary housing of a device, and FIG. 4Dshows coupling of the primary housing and the secondary housing.

Referring now to FIGS. 4A-4D shows parts of a thermal defogging systemaccording to one embodiment. The embodiment shown in FIGS. 4A-4D issimilar to the embodiment shown in FIGS. 3A-3C, except that in theembodiment shown in FIGS. 4A-4D, the secondary housing does not includea defogging element. Instead the defogging element is integrated intothe primary housing of the optical instrument—similar to as shown inFIGS. 2C-2D. In the embodiment shown in FIGS. 4A-4D, instead of having adefogging element—the secondary housing has a transparent element orwindow that is aligned with the aperture in the primary housing so thatoptical signals can be transmitted from the optical device to theexternal environment. The secondary housing forms a protective sleevesimilar to that of the secondary housing described with respect to theFIGS. 3A-3C. In the embodiment shown in FIG. 4D, where the primaryhousing is coupled to the secondary housing, heat is thermallycommunicated from the defogging element that is supported by the primaryhousing, to the external surface of the transparent element or window inthe secondary housing.

Referring to FIGS. 4A and 4B show different views of the primary housingof the optical instrument. The optical instrument includes a primaryhousing 250, a defogging element 100, and electrical connectors 360. Inone example, the defogging element 100 is substantially similar topreviously described thermal defogging elements. The primary housing 250may house optical elements 220 (i.e. prism, power source, actuator,etc.), which make up the components of an optical instrument such as ascanning device, scope, etc.

In the example shown in FIGS. 4A-4B, electrical connection is made viaelectrical connectors 360. The electrical connectors 360 shown in FIGS.4A-4B provide electrical connection to the defogging element 100. It isappreciated that instead of having electrical connectors 360 other typesof connectors may be used such as the ones described in FIGS. 1C and1E-H. Furthermore, it is appreciated that power may be supplied throughother means, e.g., magnetic field, optically, etc., as discussed above,thereby eliminating the need to have electrical connectors. Powersupplied to the defogging element 100 causes the conductive coating ofthe defogging element 100 to heat up.

Referring to FIGS. 4A and 4B, shows a defogging element 100 that isaligned with an aperture formed by the primary housing. In theembodiment shown in FIGS. 4A and 4B, the defogging element istransparent and is positioned within the aperture of the primary housing250 of the optical instrument. The transparency of the defogging element100 allows optical signals to travel between an optical element 220 ofthe optical device to the external environment without significantoptical signal degradation. The internal surface 232 of defoggingelement faces the optical element 220 within the optical device. Theexternal surface 234 of defogging element faces the external environment295. Furthermore, the defogging element 100 is not limited to theillustrated horizontal configuration. For example, the defogging element100 may be positioned such that it is angled to have particularproperties, e.g., refracting properties, reflecting properties, lightindex matching properties, etc.

Referring now to FIG. 4C shows a secondary housing 310 of an opticaldevice according to one embodiment is shown. The implementation shown inFIG. 4C is similar to the implementation shown in FIG. 3A, except thatin FIG. 4C instead of a defogging element—a transparent element 450 isaligned with and is positioned to cover the aperture 340 of thesecondary housing. The defogging system shown in FIG. 4C includes asecondary housing 310, supports 320, and a transparent element 450. Thesupports 320 are attached to or extend from the secondary housing 310and hold the transparent element 450 in place. In one embodiment, thetransparent element 450 is a substrate similar to that described in FIG.1A comprised of a material having high optical transmission propertiessuch as glass, plastic, polycarbonate, etc. Referring now to FIG. 4Dshows coupling of the secondary housing to the primary housing so thatthe primary housing fits inside and is physically located inside of thesecondary housing according to one embodiment. In this embodiment, atleast a portion of the primary housing 250, the defogging element 100,and its electrical connectors 360 are all surrounded by the secondaryhousing 210 with its supports 220 holding the transparent element 450 inplace. According to one embodiment, a gap 430 is formed between thetransparent element 450 and the defogging element 100. For example, thegap may be 0.3 mm.

In one embodiment, the gap 430 contains air. However, it is appreciatedthat the gap may be filled with other gases or liquids as long as itdoes not substantially interfere with optical signal transmissions.Furthermore, the gap may be filled with other gases or liquids as longas it maintains proper heat transfer from the thermal defogging element100 to the transparent element 450. It is appreciated that a differentthickness of the gap 430 may be used based on the heat power generatedby the defogging element 100. For example, the thickness of the gap 430may be increased if the heat power generated is increased. It isappreciated that the thickness of the defogging element 100 and thethickness of the transparent element 450 may also be changed dependingon the heat power generated by the defogging element 100. For example, athickness of the thermal defogging element 100 is selected to ensurethat heat is sufficiently transferred from one end to the other end ofthe thermal defogging element 100. It is noteworthy, that the thicknessof the transparent element 450 may also depend on its application andits mechanical load. For example, the transparent element 450 must bethick enough to prevent it from breaking when in use.

Referring to FIG. 4D for example, the defogging element 100 is held inplace and is in contact with the electrical connectors 360. As such,when power is supplied, the electrical connectors 360 provide the powerto the conductive layer 120 (FIG. 1A) of the defogging element 100. Theresistance of the transparent conductive layer 120 (FIG. 1A) of thedefogging element 100 generates a heat flux that dissipates uniformlythrough the transparent substrate 110 (FIG. 1A) of the defogging element100. In the embodiment shown in FIG. 4D, the defogging element 100 isseparated from the transparent element 450 associated with the secondaryhousing 310 via a gap 303. The generated heat from the conductive layer120 is transferred from the defogging element to the transparent elementof the secondary housing via a gap 303.

For the case where the conductive layer 120 is formed on the internalsurface of the defogging element, the generated heat flux is thermallycommunicated from the internal surface 232 of the defogging element tothe external surface of defogging element 234 through the gap 430 to theinternal surface of transparent element 452. Heat is then thermallycommunicated through the transparent element 450 and flows to theexternal surface 454 of the transparent element. As such, condensationformed on the external surface of transparent element 454 due to adifference in temperature of the ambient air and the body cavity isreduced. In one example, the oral cavity is approximately 36.5° C. andheating the defogging element 100 to 38° C. eliminates condensation andfog formed on the external surface 454 of transparent element 450.

The secondary housing 310 prevents fluids and other contaminants fromreaching the primary housing 250 of the optical instrument. Thesecondary housing 310 and the transparent element 450 of the secondaryhousing may be removable. For example, the secondary housing 310 may beremoved, disinfected, and reused for different patients. In analternative embodiment, the secondary housing may be disposable andreplaced with a new one for each patient. Further, it is appreciatedthat transparent element 450 may also be removed to be disinfectedand/or disposed and replaced. Referring to the implementation shown inFIG. 4C, the defogging system shown can be described as a secondaryhousing, the secondary housing defining a window for transmission ofoptical signals; and a transparent element 450 housed within thesecondary housing 310, the transparent element 450 adapted to be alignedwith the aperture of the secondary housing and with a defogging elementthat is aligned with the aperture of a primary housing of an opticaldevice for generating optical signals, wherein responsive to theapplication of power to a transparent conductive layer of the defoggingelement, the transparent conductive layer generates heat that isthermally communicated to the external surface of the transparentelement housed within the secondary housing.

It is appreciated that the temperature of the defogging element 100 maybe controlled using a controller, discussed below. Moreover, it isappreciated that the medical device may be programmed to reach andmaintain a desired temperature depending on its application and thesurrounding temperature. Temperature control of the defogging element isdescribed in more detail with respect to FIGS. 5 and 6 below.

Referring now to FIGS. 5A-5C, positioning of temperature sensorsassociated with the thermal defogging element according to variousembodiments is shown. In FIG. 5A, a primary housing 210, a defoggingelement 100, and a sensor 520 are shown. The primary housing 210 may besimilar to that of FIGS. 2A-2D, 3A-3C, 4A-4D. The defogging element 100is similar to the thermal defogging element, as described above. In oneembodiment, the sensor measures the temperature associated withtransparent element 110. In an alternative embodiment, the sensor 520measures the temperature associated with the conductive coating layer120 (FIG. 1A) of the thermal defogging element 100. The sensor 520 maybe positioned in close proximity to a side facet of the defoggingelement and away from electrical bars. The sensor 520 may be a thermoresistor that changes its resistance in different temperatures, therebymeasuring the temperature. In another embodiment, the sensor 520 may bethermocouple sensor with two dissimilar conductors in contact togenerate a voltage when heated. It is appreciated that in oneembodiment, the sensor 520 may be touching the side of the thermaldefogging element 100 facing the optical element 220. In an alternativeembodiment, the sensor may be touching the side of the thermal defoggingelement facing the external environment. In one embodiment, the sensor520 may be an optical sensor configured to sense infrared radiation froma heated object, thereby measuring the temperature. The sensor 520 mayor may not touch the upper layer of the thermal defogging element 100 ifan optical sensor is used. It is appreciated that use of one sensor isexemplary and not intended to limit the scope of the embodiments. Forexample, two or more sensors may be used positioned in differentlocations to obtain a better average measurement of the temperature.

Referring now to FIG. 5B, a thermal defogging element 100 similar tothat of FIG. 1C is shown. In this embodiment, a sensor 570 is positionedon a side facet of the thermal defogging element away from theelectrical bars 160. It is appreciated that the sensor may be a thermoresistor, a thermocouple sensor, or an optical sensor, to name a few.

Referring now to FIG. 5C, a thermal defogging element according to oneembodiment is shown having more than one temperature sensor. Forexample, the thermal defogging element 500C may include sensors 520,522, 524, and 526. As discussed above, a number of different sensors maybe used. For example, the sensors 520, 522, 524, and 526 may be acombination of a thermo resistor, a thermocouple sensor, or an opticalsensor, to name a few. It is appreciated that particular sensorsmentioned above are merely exemplary and not intended to limit the scopeof the embodiments. The temperature measured by the sensors in thisembodiment may be averaged to obtain a more accurate measurement. In adifferent embodiment, the highest and the lowest measure temperature maybe discarded and the remaining measured temperatures may be averaged.

It is appreciated that in one embodiment, the sensor is configured todetect temperature associated with the generated heat. In oneembodiment, the sensor is selected from a group consisting of thermalresistor sensor, a thermocouple sensor, and an optical sensor. Thecontroller is configured to adjust the power provided to the thermaldefogging element based on the detected temperature.

Referring now to FIG. 6 shows a thermal defogging system 600 accordingto one embodiment. The system 600 may include a controller 610, one ormore sensors 620, a defogging element 630, and a power supply 640. Thedefogging element 630 and the one or more sensors 620 operatesubstantially similar to those discussed above. In this embodiment, oneor more sensors 620 measure the temperature of the defogging element 630of the thermal defogging element. It is appreciated that in analternative embodiment, the temperature of the conductive coating layerof the defogging element may be measured. In one embodiment, thetemperature of the transparent substrate of the thermal defoggingelement may be measured.

In one embodiment, the measured temperature is communicated to thecontroller 610. The controller 610 may include a computer readablemedium to execute instructions based on the measured temperature. In oneembodiment, the desired temperature for removing condensation may beeither hardcoded into the controller 610 or it may be entered by theuser. For example, a desired temperature for removing condensation fromoral cavity may be 38° C. The controller 610 may fetch the desiredtemperature from a memory component and compare the measured temperatureto that of the desired temperature. In response to a difference intemperature the controller 610 may adjust the amount power supplied tothe thermal defogging element 630. For example, if the measuredtemperature is below 38° C., the controller 610 may cause the powersupply 640 to provide more power to the defogging element 630. On theother hand, if the measured temperature is above 38° C., the controller610 may cause the power supply 640 to stop providing power to thedefogging element 630.

It is appreciated that according to one embodiment, the activationvoltage of the thermal defogging element may be between 4-6 Volts. Theresistance of the conductive coating layer 120 may be between 40 to 60ohms. As such, between 0.4 W to 0.6 W power may be provided to thethermal defogging element. According to one embodiment, it may take20-40 seconds to heat the thermal defogging element 630 to 38° C. whenthe temperature of the body cavity, e.g., oral cavity, is 36.5° C. It isappreciated in different applications the heating of the thermaldefogging element may take more or less time depending on thetemperatures (desired temperature and measured temperature), resistanceof the defogging element 630, and the amount of power supplied.

It is appreciated that initiation of temperature measurement may beautomatic or manual. For example, the sensors and adjustment of power tothe thermal defogging element may occur automatically in response to thedevice being turned on. On the other hand, the sensors and adjustment ofpower to the thermal defogging element may occur in response to a userselection. For example, the user may initiate the defogging function bypressing a button. It is also appreciated that initiation of thermaldefogging functionality may automatically occur in response to detectingthat the housing containing the optical instrument has moved. Forexample, a gyroscope or an accelerometer may be used to detect movement.

Embodiments described herein with respect to FIGS. 6 and 7 may bediscussed in the general context of computer-executable instructionsresiding on some form of computer-readable storage medium, such asprogram modules, executed by one or more computers, computing devices,or other devices. By way of example, and not limitation,computer-readable storage media may include computer storage media andcommunication media. Generally, program modules include routines,programs, objects, components, data structures, etc., that performparticular tasks or implement particular abstract data types. Thefunctionality of the program modules may be combined or distributed asdesired in various embodiments.

Computer storage media can include volatile and nonvolatile, removableand non-removable media implemented in any method or technology forstorage of information such as computer-readable instructions, datastructures, program modules, or other data. Computer storage media caninclude, but is not limited to, random access memory (RAM), read onlymemory (ROM), electrically erasable programmable ROM (EEPROM), flashmemory, or other memory technology, compact disk ROM (CD-ROM), digitalversatile disks (DVDs) or other optical storage, magnetic cassettes,magnetic tape, magnetic disk storage or other magnetic storage devices,or any other medium that can be used to store the desired informationand that can be accessed to retrieve that information.

Communication media can embody computer-executable instructions, datastructures, program modules, or other data in a modulated data signalsuch as a carrier wave or other transport mechanism and includes anyinformation delivery media. The term “modulated data signal” means asignal that has one or more of its characteristics set or changed insuch a manner as to encode information in the signal. By way of example,and not limitation, communication media can include wired media such asa wired network or direct-wired connection, and wireless media such asacoustic, radio frequency (RF), infrared and other wireless media.Combinations of any of the above can also be included within the scopeof computer-readable storage media.

Referring now to FIG. 7 , an exemplary flow diagram 700 of operation ofa thermal defogging element according to one embodiment is shown. Atstep 710, power is supplied to the defogging element in order to heat upthe defogging element. At step 720, the temperature associated with thedefogging element may be measured. At step 730, the measured temperaturemay be compared with the desired temperature (user entered orhardcoded). According to one embodiment, the desired temperature may befetched from a memory component storing the value. The controller, atstep 730, may adjust the amount of power supplied to the defoggingelement in order to adjust the temperature of the defogging element. Forexample, more power may be provided to the defogging element if themeasured temperature is below the desired temperature.

Accordingly, condensation and fog formed on the exterior of atransparent substrate, e.g., the thermal defogging element, thetransparent window, etc., that is in contact with patient's body cavitymay be reduced by heating up the thermal defogging element. Moreover,using the thermal defogging element eliminates the need to use a heaterwithin the medical device and using a fan to blow air, thereby reducingthe size of the medical device while eliminating noise generation.Furthermore, using the thermal defogging element does not interfere withoptical signals and it further reduces the amount of power being used bythe device to remove the condensation.

The foregoing description, for purpose of explanation, has beendescribed with reference to specific embodiments. However, theillustrative discussions above are not intended to be exhaustive or tolimit the embodiments to the precise forms disclosed. Many modificationsand variations are possible in view of the above teachings.

What is claimed is:
 1. An intraoral scanning device, comprising: ahousing comprising: a head configured for insertion into an oral cavityof a patient, the head comprising a sloped surface and an aperture fortransmission of optical signals; a transparent element positioned withinthe aperture, wherein the transparent element is at an acute angle withrespect to the sloped surface; and a defogging unit comprising a heatingunit; and a protective sleeve configured to cover at least a part of thehead when the protective sleeve is coupled to the housing, theprotective sleeve comprising: an additional aperture that aligns withthe aperture; and an additional transparent element in the additionalaperture; wherein the housing and the protective sleeve are configuredsuch that a gap separates the additional transparent element from thetransparent element when the protective sleeve is coupled to thehousing; wherein the heating unit is configured to generate heat inresponse to application of electrical power to the heating unit; andwherein the housing and the protective sleeve are configured such thatthe heat generated by the heating unit is transferred from the heatingunit to the additional transparent element despite the gap thatseparates the additional transparent element from the transparentelement.
 2. The intraoral scanning device of claim 1, wherein the gap isan air gap.
 3. The intraoral scanning device of claim 1, wherein theprotective sleeve is removably coupled to the housing.
 4. The intraoralscanning device of claim 1, wherein the heating unit comprises atransparent conductive layer on a surface of the transparent element. 5.The intraoral scanning device of claim 1, further comprising: a flexcircuit that connects to electrical bars of the heating unit to deliverelectrical power to the heating unit.
 6. The intraoral scanning deviceof claim 1, further comprising: one or more temperature sensors disposedproximate to the transparent element.
 7. The intraoral scanning deviceof claim 1, wherein the protective sleeve comprises plastic.
 8. Theintraoral scanning device of claim 1, wherein the transparent elementhas an optical transmission of at least 90%.
 9. The intraoral scanningdevice of claim 1, wherein the transparent element has a thickness of0.75-1.0 mm.
 10. The intraoral scanning device of claim 1, wherein thetransparent element comprises at least one of glass, plastic orpolycarbonate.
 11. The intraoral scanning device of claim 1, furthercomprising: an insulating layer that covers a surface of the transparentelement.
 12. The intraoral scanning device of claim 11, wherein thesurface of the transparent element covered by the insulating layer facesan external environment.
 13. The intraoral scanning device of claim 1,further comprising: an anti-reflective layer that covers a surface ofthe transparent element.
 14. The intraoral scanning device of claim 1,wherein the intraoral scanning device comprises a longitudinal axis, theintraoral scanning device further comprising: a first electricalconnector on a first side of the transparent element along thelongitudinal axis; and a second electrical connector on a second side ofthe transparent element along the longitudinal axis; wherein the firstelectrical connector and the second electrical connector deliverelectrical power to the heating unit.
 15. The intraoral scanning deviceof claim 1, wherein the protective sleeve is replaceable.
 16. Theintraoral scanning device of claim 1, wherein the protective sleeve isreusable.
 17. The intraoral scanning device of claim 1, furthercomprising: modular contacts for the heating unit.
 18. The intraoralscanning device of claim 1, wherein the housing and the protectivesleeve are configured such that the heat generated by the heating unitis transferred from the heating unit to the additional transparentelement via convection.
 19. The intraoral scanning device of claim 1,wherein the housing and the protective sleeve are configured such thatthe heat generated by the heating unit is transferred from the heatingunit to the additional transparent element via conduction.
 20. Theintraoral scanning device of claim 1, wherein the defogging unit isconfigured to transfer sufficient heat to the additional transparentelement to prevent condensation from forming on the additionaltransparent element.
 21. The intraoral scanning device of claim 1,wherein the sloped surface of the head is sloped with respect to alongitudinal axis of the housing.